According to research, the brain’s dimensions, contours, and grooves may influence how well it functions – possibly even more so than the connections between its neurons.
Even though there are many unanswered questions regarding the brain, researchers have long hypothesised that the billions of interconnected neurons that convey signals to one another and allow communication between different parts of the brain are what cause our thoughts, feelings, and behaviours.
The brain’s size, curves, and grooves may have a greater impact on how we think, feel, and act than the connections and messages between neurons, according to a study published on Wednesday in the journal Nature.
After performing MRI scans on the brains of 255 volunteers while they were engaged in activities like tapping their fingers or memorising a series of images, a research team in Australia concluded. To further evaluate the impact of brain shape, the team then looked at 10,000 distinct maps of people’s brain activity compiled from more than 1,000 trials conducted worldwide.
They then developed a computer model to simulate how the size and form of a brain affect electrical activity waves or brain waves. They compared that model to an earlier computer simulation of brain activity that closely matched the theory that neuronal connection is the primary regulator of brain activity.
The comparison revealed that the new model, as opposed to the old one, offered a more precise reconstruction of the brain activity depicted in the MRI images and brain activity maps.
James Pang, a research fellow at Monash University in Australia and the study’s principal author, compared the importance of brain shape to a pebble creating ripples in a pond: The size and form of the pond influence the type of ripples created.
“The geometry is pretty important because it guides how the wave would look, which relates to the activity patterns you see when people perform different tasks,” Pang said.
According to Washington University in St. Louis neuroscience professor David Van Essen, the brain shape theory has been discussed for more than ten years. However, he claimed that most researchers continue to support the conventional theory, which holds that each of the brain’s nearly 100 billion neurons, or nerve cells, contains an axon that serves as a wire to transmit information to other neurons, enabling brain activity.
“The fundamental starting hypothesis is that the wiring of the brain is central to understanding how the brain functions,” stated Van Essen.
According to Pang, his research does not undervalue the importance of neuronal communication; rather, it implies that the geometry of the brain is more crucial to brain function.
“What the work is showing is that the shape has a stronger influence, but it’s not saying that connectivity is not important,” he said.
The brain shape theory, according to Pang, has the benefit of being simpler to measure than brain circuitry; thus, paying more attention to the size or curves of the brain may lead to new lines of inquiry.
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He said that one area worth researching is the potential contribution of brain structure to the emergence of neurological and mental disorders.
According to Pang, the rate at which travelling waves spread to various brain parts may impact how individuals process information. This could then influence the brain activity patterns linked to illnesses like schizophrenia or depression.
However, not all scientists are persuaded by the new findings. Van Essen, for example, continues to be dubious.
“It would be an understatement to say this is a controversial theory, and it needs to be put through its paces to evaluate critically whether it stands the test of time,” he said.
Van Essen cited several issues with the study, including the fact that the models used by the researchers are averages based on participant brain shapes. Van Essen claims the method obscures the stark variations in surface fold patterns between different brains.
Pang asserted that the results “remain robust” even after completing a brain shape study at the individual level.
Van Essen also warned that MRIs are unreliable instruments and might not accurately depict how the brain is wired.
“As exciting and informative as it is, it’s still inaccurate in fundamental ways and incomplete, and leaves a lot left to be sorted out by future studies,” he said of MRI technology.
Pang acknowledged that his research isn’t conclusive but said that, in his opinion, the new study “strengthens the theory” that brain shape affects brain activity more so than neuronal wiring.
“We’re pretty confident that the influence is there,” he said.